1. Field of the Invention
The present invention relates to a process for treating contaminated gas, and more particularly to a catalytic oxidation process involving control of the oxidant feeding amount by means of continuous monitoring of the organic compound concentration and oxidant concentration in the emitted gas.
2. Description of the Prior Art
Presently, environmental issues are a major concern in the manufacturing industries. Waste gas containing volatile organic compounds (VOC) must be treated according to government regulations. Treatment technology for waste gas can be generally classified into three types: incineration, adsorption by activated carbon, and advanced catalytic oxidation at ambient temperature. Incineration requires high heat levels. Adsorption by activated carbon requires frequent changing of the carbon, resulting in large amounts of waste. High level catalytic oxidation process requires a temperature higher than 200° C.
U.S. Pat. No. 5,755,977 discloses a catalytic oxidation process at ambient temperature (20° C.-30° C.). Contaminated air containing VOC is treated by an oxidant such as ozone or hydrogen peroxide and an iron oxide catalyst. However, the treatment efficiency is relatively low with waste gas with high humidity (higher than 20%). The removal ratio of waste gas containing trichloroethylene (TCE) is lower than 30%. Moreover, the utility rate of the oxidant is low; thus, excess oxidant is emitted. Since ozone is generally used as an oxidant and considered as a toxic compound, its toxicity causes air pollution.